The purpose of this reseach is to investigate the conceptual basis of spontaneous speech production. That is, to investigate the processes by which speakers build up utterances as they encode concepts and find ways to interrelate them. The view is presented, that units of speech production correspond to such concepts as objects, actions, states, and events, and that there are syntactic processes which specialize in the encoding of each of these concepts. As the speaker proceeds, he moves from concept to concept, and recruits the appropriate syntactic processes, which produce the corresponding segment of surface structure. The approach is in part theoretical and includes: a new theory of the syntagma; a descriptive method for representing conceptual structures; and an investigation of selected syntactic structures from a production point of view. In part the approach is experimental and observational and consists of studies of: spontaneous speech; spontaneous gestures during speech; speech timing; hesitations; and individual styles of conceptual organization during the production of speech. Both the theoretical and empirical studies are tied together by the general view mentioned above.